1. Field of the Invention
The present invention relates to a dispensing apparatus, and more particularly to a dispensing apparatus for dispensing liquids, pressurized gas, and mixtures of liquids and pressurized gas in various concentrations.
2. Description of the Background of the Invention
Various devices exist for dispensing mixtures of liquids and pressurized gas. For example, U.S. Pat. No. 4,005,825 to Schowiak discloses an apparatus whereby the individual components of a multiple component sprayable fluid are conducted through separate lines to a hand-held unit, mixed in a mixing manifold, and are subsequently atomized in an air atomizing spray gun by air conducted through a separate line. U.S. Pat. No. 3,059,858 to Linder discloses an applicator system whereby compressed air, detergent and water travel through separate lines to a hand-held unit. The liquid detergent and water lines may be turned off, permitting an air alone operation.
Devices such as these allow chemicals or liquids to remain unmixed until just before they are dispensed as a mixture or aerosol. Unfortunately, they also entail at least three or more separate lines running to a hand-held unit. Specifically, those devices require a separate hose for conducting pressurized air to be run from a pressurized air source to a hand held device. Furthermore, such a large number of lines running to a hand-held unit tends to make the unit much more cumbersome and difficult to use. Such devices often require separate sources of air pressure for forcing the liquid through the various hoses and for mixing with the liquids in the hand held devices to propel the liquids in the form of an aerosol.
Other devices overcome at least one of these problems in that a single source of pressurized air is used as both as a mixing agent and as a means to pressurize the liquid(s). For example, U.S. Pat. No. 773,852 to Cutting discloses a powder and liquid distributing device wherein air from a single source of pressurized air is supplied separately to both a chemical discharge chamber to aid in moving the chemicals along distributing pipes, and to a hand-held atomizing unit to atomize a chemical as it leaves a distributing pipe. East German patent Publication No. 251,926 discloses a device whereby a supply of pressurized air is supplied separately to a spray gun and to a fluid reservoir to pressurize fluid in the reservoir. Those devices still have the disadvantage, however, that they require a separate air hose running to a hand-held unit, and therefore present more cumbersome and difficult to use hand-held units.
U.S. Pat. No. 1,537,566 to Temple discloses a painting device in which compressed air is supplied to a tank to pressurize the paint. The pressurized air is then taken from the tank to a paint spray nozzle. An air hose extends within a paint hose over at least a portion of their respective lengths so that only one line extends toward the spray nozzle over at least a portion of the length of the hoses. However, the air and paint hoses come out of the tank separately and thus form two lines along a beginning portion of their lengths which tends to increase the complexity of the device. Also, the device does not include control valves for the air and paint lines near the spray nozzle, which makes it difficult for a user to quickly control the flows of air and paint.